Recent Canadian Floods Beg for Intelligent Discussion on how to Allocate Finite Capital: Mitigation vs. Adaptation

Recent catastrophic flooding in Toronto and Calgary have, for the moment, captured the attention of the public and politicians. So, how can we take advantage of this attention to address the somewhat intractable problem of how Canada, going forward, should address climate change and extreme weather events?

A flooded Calgary Stampede stadium is seen from a aerial view in Calgary, Ab. Saturday, June 22, 2013. (Jonathan Hayward/The Canadian Press)

Three courses of action to address extreme weather are possible.

First, as has been popular in the media of late, many Canadians believe the country should double-down on efforts to limit emissions of greenhouse gases, either by embracing various forms of renewable energy, or by imposing a carbon tax or cap-and-trade system on fossil fuels. Second, others lean towards incorporating adaptation into the way we build infrastructure — that is to say, for example, building larger diameter sewer drain pipes that can accommodate larger volumes of rain and hence reduce the probability of flooding. And third, some people believe we should pursue both courses of action — mitigation and adaptation.

Let’s consider each of the above options. Also, keep in mind that governments at all levels — federally, provincially and municipally — are cash strapped. So, every dollar spent on one initiative is a dollar not spent on another — everything is a trade-off, so the optimal allocation of resources relative to money, time and brain power is the core issue.

In reference to the first option, embracing renewable energy or imposing some form of tax to reduce greenhouse gas emissions, Canada must ask itself how this action will impact global greenhouse gas loadings. According to the International Energy Agency, about 70% of world energy supply is currently derived from about one-third each of coal, oil and gas (with China and India being the largest consumers) — the remaining supply comes from a mixture of nuclear, hydro, biomass and other renewable sources. In 2030, the picture will not change much in terms of the percentage contribution of fossil fuels to supply the world’s energy, and this assumes optimistic scenarios of additional renewable sources and aggressive energy conservation efforts. The more lamentable, yet real, factor in the equation is this — total world use of fossil fuel will increase by about 13% by 2030, over current use, driven largely by population growth. Currently, the world’s population grows by about 11,000 people per hour net (subtracting deaths from births), which translates to about 90 million people per year. By 2030, there will be another 1.5 billion people on the planet that will require energy — not to mention food and habitable space, both of which will be increasingly limited due to climate change.

Accordingly, the energy equation for the future — which is fossil fuel dependent — will not change much regardless of efforts to embrace renewable energy, or Canadian efforts to reduce greenhouse gas emissions through the imposition of taxes. The argument can be made that by imposing a carbon tax, Canada might send a public relations signal globally that could enhance its reputation and ability to do business abroad — there is merit to this argument. Similarly, if revenue derived from a carbon tax was directed towards adaptation efforts, this could be useful. However, in the end, Canadians should not live delusionally — global energy supply will be fossil fuel based independent of any action Canada takes.

The second means by which Canada can address extreme weather is to adapt by weather-hardening infrastructure to withstand high intensity and duration rainfall events, excessive wind and temperature and ice storms. Additionally, behavioural modification — for example, developing up-to-date flood plain maps and subsequently not building houses where flooding is likely to occur — can also prove rewarding.

The determination of how and where infrastructure should be weather-hardened must take three factors into account — initiatives must be practical, meaningful and cost-effective.

Consistent with these criteria, one form of adaptation — that many Calgarians and Torontonians can now appreciate — relates to the need to mandate that for all new house construction in Canada (barring exceptions for obvious outliers such as mountain top properties), backwater valves be installed in the drains in basements. The need for these valves is great — for example, in the early 1990s, basement flooding replaced fire damage as the most expensive claim on home insurance. This growing cost is attributable, at least in part, to an overall increase in the magnitude of rainfall events, which can overburden sewer lines such that water backs up through the system causing basements to flood. Although the costs of sewer back up are not yet fully tabulated for recent events in Toronto and Calgary, the cost for earlier extreme weather flooding has been calculated. For example, one three-hour rainfall in August of 2005 of over 160 mm resulted in 13,000 flooded basements in Toronto, resulting in $500-million in property damage. If a backwater valve, which costs about $300 to install during new home construction, had been present in these homes, much of the $500-million price tag could have been avoided.

Canada can adapt by weather-hardening infrastructure to withstand high intensity and duration rainfall events, wind and temperature and ice storms.

Within cities and surrounding rural areas, other adaptation initiatives, such as leaving wetlands intact, can prove extremely useful in alleviating the otherwise devastating impacts of flooding — there is effectively no cost to leaving such “key capacitor” wetlands in place, other than the spurious argument of the opportunity cost of not building on wetlands.

When infrastructure within cities is being replaced or built new, it should be upgraded taking extreme weather conditions into account. For example, at the time of new build, the cost of installing a 20 cm sewer drain pipe is immaterial relative to the cost of installing a 30 cm drain pipe (which has about twice the flow capacity), yet the larger capacity line may save untold $millions if it eliminates future sewer back-ups. Conversely, if new inadequate piping is installed — or any form of infrastructure — and it is later found to be inadequate relative to extreme weather and a retrofit is required, such needless expense is a poor use of limited capital.

Other forms of adaptation that can be developed in cities to adjust to the new normal of extreme weather include building permeable surface parking lots. Such parking lots, that look like a checker board of brick interspersed with gravel or grass that will let water percolate down to the groundwater, can limit overland flooding. Similarly, bioswales, which are ditch-like structures filled with gravel and plants, can adsorb run-off and return it to the groundwater, rather than the water flowing overland and potentially flooding basements. Bioswales spread strategically throughout cities can be cost effective means to limit flooding.

The return on investment to install or build backwater valves, permeable parking lots, bioswales, flood retention ponds, sewer upgrades and a myriad of other infrastructure enhancements is positive, particularly given the extreme weather events that are yet to come, and that will be equal to or in excess of those observed in Canada most recently. Despite a positive return on investment, fiscal resources to build weather-hardened infrastructure are limited, which brings this discussion back to the consideration of the optimal allocation of resources dedicated to mitigation vs. adaptation.

Where mitigation efforts can be applied under an 80:20 rule — that is to say, realizing an 80% reduction in emissions for 20% of the cost that would otherwise be spent to eliminate emissions 100% — this may make sense to slow down (as we cannot stop) climate change. However, when capital is directed to net zero greenhouse gas emissions, which can be enormously costly, this is probably a poor use of funding that could otherwise be applied to adaptation. It is also not inconsequential to note that any benefits that accrue due to mitigation are global in nature, and can only make a difference if other countries in the world similarly reduce their use of fossil fuels — clearly, based on aforementioned International Energy Agency projections, fossil fuel use is not going to drop any time soon. Conversely, for every dollar spent on mitigation in Canada, the benefits of that dollar will be material and remain in Canada.

Canada needs an informed national discussion pertaining to the optimal allocation of effort to be directed to mitigation vs. adaptation — the discussion should be based on fact, and not utopian wishful thinking. While there is a window of attention, before blue skies divert the attention of the public and politicians, that debate should be scheduled — otherwise, management by disaster will continue to rule the day.

This article was originally published in the National Post
_________________________Blair Feltmate is Associate Professor, and Director of Sustainability Practice, in the School of Environment, Enterprise and Development (SEED), Faculty of Environment, University of Waterloo.

You make it sound like Engineers etc have not taken these ideas in account already. Storms are a statistical quantity, typical a 1 in 50 year storm event is taken into the design factor. You may argue that it needs to be a 1 in 100 years , but that has a large price impact. Sewers are not enlarged- as they are meant to have a scour velocity so they self clean. Nations are only getting around to the costing of having a dedicated pipe for storm water and another for waste water, but as you can already guess , that doubles the cost. Mother earth is very capable of breaking down human waste , it struggles though, when millions of people get together, lay lots of concrete and asphalt, in a place called a City. So how about spacing out our living footprint, say 1 family property per 1000 sq m. with less hard surfaces.
I’m stunned that you say fitting a non-return valve is an option ing house basement. Whose idea was that. They should be made to clean out all the basement in pence.